Actuating mechanism for engine fuel pumps



Dec. 15, 1931. P. CLEIRGEIT 1,836,645

ACTUA'IING MECHANISM FOR ENGINE FUEL PUM PS Filed Jan. 10, 1930 5Sheets-Sheet 1 IN VeNTaR 15, 1931. P. CLERGET 1,836,645

ACTUATING MEcHANisM FOR ENGiNE FUEL FUMPS Filed Jan. 10, 1936 3Siieis-fihi: 3

FC/eryef nil- .5.

Patented Dec. 15, 1931 UNITED STATES PATENT OFFICE PIERRE GLERGET, FPARIS, FRANCE ACTUATING- MECHANISM FOR ENGINE FUEL PUMPS Applicationfiled January 10, 1930, Serial No. 419,991, and in France January 11,1929.

This invention relates to the general technics of mechanisms comprisingdriving members constituted by cams, receiving continuous circularmovements, and driven members which must receive periodical movements.

Such mechanisms are currently applied to the valve gear of heat enginesand present the following particularity: 7 When it is desired to imparta movement '10 of great acceleration to a driven member, such as atappet, for instance, the angle of engagement of the cam is limited, fora given stroke of the tappet, by the application of r a wedging actionof the cam against this '15 tappet. Thus.- in the case of an explosionengine operating on the four stroke cycle, and the cam of which insuresthe distribution of fuel must rotate at a speed one half as fast as thespeed of rotation of the engine shaft, it is necessary, to obtain alifting of the valves, which isboth rapid and gives a strokeofsufiicient amplitude, either to interp'ose amplifying mechanismsbetween the valve and the tappet directly engaged by the cam, or to giveto the neutralsurface of the cam a diameter lying within angles ofengagement which does notcause wedging.

The present invention has forits object a "'0 driving mechanism by meansof cams, which do not present the inconveniences above mentioned. Thisimproved mechanismobtains, with camsof' reduced dimensions, greataccelerations of the driven parts at angles of engagement Withoutcausing insufficient strokes or wedging.

Such a mechanism is mainly characterized in the new combination. with atleast one cam and one member to be driven, of an intermediate movablemember synchronized with the movement of the cam, in such a manner that,the latter being capable of rotating as fast as desired, the movablemember interposes itself between the cam andthe member to be driven, atthe required moment.

Such as defined by its principle, thepre'sent invention can be carriedout according to various forms of construction which can differ fromeach other particularly by the nature" of the movement adopted for theinter- '50 mediate movable member arranged between the cam and thedriven member, and its kinematic connection with the cam.

A particularly convenient form of construction is characterized in thatthe kine fis matic connection between the cam and the intermediatemember is an epicycloidal connection, the same being capable of ensuringthe actuationof several members radially arranged.

The accompanying drawing illustrates, by way of example only, amechanism such as above characterized;

Figures 1 to 7 are diagrammatic views intended to illustrate theconsiderations set "t5 forth in the: foregoing.

Figures 8 to 10 are detail views of a slightly modified arrangement,shown respectively'i-n plan, in-axial section and in cross section.

Figure 11 is a front view,with partial cross section, of the entiremechanism with epicycloidal connection.

Figure 12 is an axial section made accord ing to line AA of Fig. 11. F

If a (Fig. 2) is the total angular stroke of a cam rotating at the speedof the driving shaft and [3 the corresponding angle for a cam having thesame pitch diameter, rota-ting at half the speed of the driving shaft,it will be seen that the lifting of the valve'in the second case, isdistinctly smaller than that obtained in the first case. In both cases,the flanks of the cam are, foravoiding wedging, tangent to thecylindrical pitch surface of the cam.

The principle of the invention is illustrated in one of its forms ofrealization on Fig;- 4. An intermediate member or slide-block 1,radially movable in a support rotating about the cam,comes, atpredetermined moments,

between the cam 2 and the member to be driven. If the slide-block 1 isdriven about the cam 2, in reverse direction to the rotation of thelatter, the angle a expressing the angular displacement of the camcorresponding to the length of the action of the latter on the drivenmember, is reduced in the ratio of the angles a and B, or being the realangle of engagcment of the cam 2 and ,8 the angular displacement of theslide-block as long as it remains in contact with the cam. It will beseen that in these conditions for one and the same stroke ordisplacement A of the driven member, the duration of this displacementis less and, consequently its speed greater, and conversely than with acam in direct contact with the driven member. To this advantage,

it must be added that the speed of the cam can be as high as desired,since its periods of action on the driven member are determined by themovement of the slide-block 1, and

not by its real passages opposite the driven member.

The support ofjthe slide-block or slideblocks 1 can rotateconcentrically with or eccentrically to the cam 2. In the example ofFig. 5, the support or guide 3 rotates concentrically with the cam 2, athalf the speed of the latter and in reverse direction thereto. Thecoincidence between the cam 2 and the slide-block 1 occurs once everytwo revolutions. It results from this particularity that the engagementof the cam and slide-block can occur every two-thirds of a revolutionand that it is thus possible to actuate three tappets arranged at 120degrees apart. In Fig. 6, the guide 3 rotates eccentrically to the cam2, but the principle of the operation remains the same. In Fig. 7, theguide 3 receives both a gyratory movement about the cam 2, and arotation about the axis which imparts to it a gyratory movement. Withthe exception of the kinematic connection between the cam 2 and thesupport 3, the arrangement remains the same as that already indicated. v

In the example of Figs. 8, 9 and 10, which are respectively a plan view,an axial section and a cross section of one and the same arrangement,the driven member or members or tappets 4, as well as the slide-blocks,are arranged parallel to the axis of the driving shaft 5. The support orguide 3 is in the form of a planet wheel loosely mounted on a trunnion 6of the driving shaft 5 and rolling without sliding on internal teeth 7concentric with the driving shaft; the cam or'cams 2 are carried by anarm 8 of the driving shaft. It will. be seen that it is always possibleto provide a kinematic connection, between the cam or cams and themember or members'to be driven for obtaining any desired positioning ofthe said members relatively to the cams. Moreover, by causing theangular position of the teeth 7 to vary by means of a control 0011-nected to the arm 7 it is possible to modify the angular positions ofthe driving shaft for which occur the moments of engagement or ofrelease of the driven members or tappets; in other words, advance orretardation can be obtained in the movements of actuation.

Figs. 11 and 12 illustrate a form of carrying out the invention appliedto the control of fuel injection pumps on an internal combustion enginehaving nine cylinders radially arranged. In this form of construction,application is made of the principle diagrammatically shown in Fig. 1,and which comprises a single cam 2, a rotary guide 3, with multipleslide-blocks 1, rotating concentrically with or eccentrically to thedriving shaft, in order to ensure the periodical actuation of tappets 4radially arranged.

In this example of construction, it is necessary to successively actuatenine injection pumps for nine cylinders, the phases of which occur everyeighty degrees of rotation of the driving shaft.

The driving shaft 5 is provided with a double helical incline on whichis fitted a cam 2 provided with a double annular flange 10 forming agroove for one or more rollers arranged at the end of a lever 11, or ofa fork pivoted on an axis 12 of the fixed frame of,

the engine which allows, by means of any suitable operating rigging, ofmodifying the position of the cam on the shaft 5.

The guide or support for the slide-block 3 is coaxially arranged to theshaft 5; it is centered on the latter and can be made of severalsections suitably connected, for allowing the assemblage of the cam. Itis provided with four guide slides for four radial slide-blocks 1 spaced90 degrees apart and:

which move in the plane common to nine tappets returned in thecentripetal direction by springs 13 and attached, through rods 14, tothe pumps to be actuated (not shown in the drawing). The tappets 4 areguided in radial bearing portions of the fixed frame of the engine andare provided with tops or abutments 15 for limiting their centripetaldisplacements.

The guide 3 is provided with a plate 3 on 1:

set of gears thus obtained is such that the guide 3 rotates in reversedirection to the cam 2 and at a speed equal to of that of the drivingshaft 5. Fixed cams or inclines 22 are provided for returning theslide-blocks 1 in the centripetal direction, so as to avoid anyprejudicious shocks on the heel portions of the tappets 4. These arcuateheel portions are adapted to allow a displacement of the slide-blocksrelatively to the tappets, without the latter ceasing to be actuated bythe said slide-blocks at the required moments, between limits determinedby the circumferential extent of the heel portions 4*.

It is to be noted that the device thus constructed effects two distinctadjustments. A first adjustment is obtained by the lever 11, and asecond adjustment by the arm 20. If the two possible adjustments are inthe same direction, they are added to each other; they are subtractedfrom each other if they are of reverse directions. The plate can carrycams 23 for the control of other tappets 24, in view of obtaining anydesired result.

The pinion 21 can also be acted upon by any suitable mechanism for thepurpose of displacing it relatively to the shaft 5 and to add anadjusting element to those already mentioned. 7

It is to be noted that the inclines 22, the function of which has beenindicated above, can, if necessary, be angularly displaced at the sametime as the slide-block 1. For that purpose, the inclines are formed ona crown 22*, provided with an operating lever 22*, independent, orkinematically connected, by any suitable mechanism, to any of thearrangements which permit the modification of the position of theslide-blocks relatively to the cam.

The mechanism which has just been described is a simple example ofcarrying out the invention. The latter is defined by the features setforth in the present specification, and, whatever may be theapplications of the same, it includes in its scope, all the means andcombinations of means suited to the carrying into practice of thesefeatures, for the purpose of obtaining the industrial result set forth.

lVhat I claim as my invention and desire to secure by Letters Patentis 1. Mechanism for periodically actuating fuel pumps on internalcombustion engines including in combination a driving cam, a drivenmember, an intermediate movable member coacting with the cam and drivenmember, and means for moving the intermediate member synchronously withrespect to the operation of the cam so that the intermediate member willbe interposed between the cam and driven member and actuated by the cam,said moving means including a rotating support in which the intermediatemember is mounted for radial sliding movement. I

2. Mechanism as claimed in claim 1, wherein the support for theintermediate member moves in a direction opposite to the direction ofrotation of the driving cam.

3. Mechanism for actuating fuel pumps specification.

PIERRE CLERGET.

